The present invention relates to a modulator of light intensity in integrated optics.
The use of the electro-optical effect revealed particularly in ferroelectric materials has enabled light modulators to be constructed, in different embodiments compatible with integration techniques with which optical waveguides are obtained in a substrate of index n.sub.o by creating zones where the index of refraction is greater than n.sub.o. One of these embodiments consists of an interferometer with two arms in which there is created, by electro-optical effect, a difference in speed of propagation in the two arms, producing an electrically controlled phase shift between the waves from the two arms. The exiting light intensity is variable with the phase shift and may then be modulated by an electric voltage inducing the electro-optical effect. It can be easily shown and experimentally ascertained that the variation of the resulting light intensity depending on the differential phase shift between the two arms is sinusoidal. Now, it is necessary in numerous applications, concerning the transmission of analog signals, to have a specific range, with linear variation, which is only verified in the vicinity of the points of inflection of the variation curve.